In the field of wireless communications, user telephones and network base stations exchange voice data over wireless communication links. The base stations exchange the voice data with one another over a backhaul communication network. Many backhaul networks are packet-based. In a packet-based backhaul network, the voice data is encapsulated in multiple packet wrappers that each include overhead information. The network elements in the packet-based backhaul network read and process the overhead information to route or switch the voice data to the intended destination system.
These packet-based backhaul communications are layered by repeatedly encapsulating the voice data in successive wrappers. In a typical scenario, a block of voice data is first encapsulated in a Real Time Protocol (RTP) wrapper with an RTP header. The RTP header includes a sequence number and a time stamp, among other information suitable for media streaming. The RTP wrapper is encapsulated in a User Datagram Protocol (UDP) wrapper having a UDP header. The UDP header includes destination and source ports, data length indicator, and checksum. The UDP wrapper is encapsulated in an Internet Protocol (IP) wrapper with an IP header. The IP header includes destination and source addresses, Diffserv marker, congestion notification, and other information suitable for packet processing.
The IP wrapper is encapsulated in an Ethernet frame. The Ethernet frame includes destination and source Media Access Control (MAC) addresses that are used for routing the Ethernet frame across an Ethernet switching system. Each of these MAC addresses is six octets in length. The typical syntax for depicting an Ethernet MAC address is AA:BB:CC:DD:EE:FF where each pair of letters represents one of the octets. The first three octets (AA:BB:CC) specify an Organizationally Unique Identifier (OUI). Organizations may obtain their own OUI from the IEEE. The last three octets (DD:EE:FF) are unique to the Network Interface Card (NIC) in the respective communication transceiver. Thus, last three octets (DD:EE:FF) are unique to a piece of hardware.